The present invention relates to a medium on which a printing control program for allowing a printing apparatus to execute printing on the basis of image data of pixels in a dot matrix state is recorded, a printing control method, and a printing control apparatus. More particularly, the invention relates to a medium on which a printing control program for executing an optimum process in accordance with printing quality is recorded, a printing control method, and a printing control apparatus.
When a computer or the like deals with an image, the image is expressed by pixels in a dot matrix state and each pixel is expressed by a gradation value. For example, a photograph or computer graphic is often displayed by pixels of 640 dots in the horizontal direction and 480 dots in the vertical direction on the screen of a computer.
On the other hand, the performance of a color printer has been remarkably improved. The color printer has dot density of 720 dpi (dots/inch) and has extremely high definition. In the case of printing an image of 640xc3x97480 dots on a dot unit basis, the image becomes very small. In this case, since the gradation values are different and the meaning itself of resolution differs, the image has to be converted to data for printing by interpolating the dots. That is, when the printed image becomes small in a one-to-one corresponding manner, a process of increasing the number of pixels of the image data (this is called a resolution increasing process or magnifying process) is performed. In the opposite case, a process of decreasing the number of pixels of the image data (this is called a resolution decreasing process or reducing process) is performed.
As a conventional method of interpolating dots in such a case, methods such as a nearest neighboring interpolation (hereinbelow, called a nearest method) and cubic convolution interpolation (hereinbelow, called a cubic method) are known. Japanese Unexamined Patent Application No. 6-225140 discloses a technique of smoothing an edge in the event of interpolating dots by preparing a dot pattern by which an image is enlarged in a shape having a smooth edge.
Although the gradation display is easy in a computer or for a display, generally, a color printer often can express only two levels, that is, whether a dot of color ink is applied or not. A gradation converting process of converting a multilevel gradation display to a two-level gradation display is therefore performed.
As described above, in order to perform printing by a printing apparatus on the basis of image data, a pixel interpolating process and a gradation converting process have to be executed.
Although the pixel interpolating process and the gradation converting process can be selected by a user interface on a computer, each of the processes is quite independent and the user separately instructs the processes while considering the picture quality and processing speed. There is, however, a problem that whether a desired result can be obtained or not depends on a combination of the picture quality and the processing speed of the processes and it is troublesome except for a skilled person.
Each of various methods such as nearest method and cubic method in the pixel interpolating process has advantages and disadvantages. It is difficult for the user to select a method. When one of the methods is fixedly used, the quality of an interpolation result of an image at which the method is not good deteriorates. Further, in the invention disclosed in Japanese Unexamined Patent Application No. 6-225140, since a pattern is prepared, an interpolation magnification has to be fixed. On the precondition of a color image, the number of patterns is enormous and it is difficult to even prepare the patterns.
Meanwhile, prior to the invention, the applicant of the invention has invented an interpolating method of interpolating image data by the cubic method and then interpolating the interpolated image data by the nearest method. By the method, high operation processing speed of the nearest method can be utilized while utilizing the high interpolating accuracy of the cubic method. In this case, 180 dpi is set as a threshold value, image data inputted is once interpolated to a value higher than 180 dpi by the cubic method and then the data is interpolated by the nearest method to a required resolution such as 360 dpi or 720 dpi as inherent printing data. That is, since a computing amount increases significantly when an interpolating process to the inherent interpolating magnification is executed only by the cubic method and jaggies are conspicuous when the interpolating process is executed only by the nearest method, in order to avoid the inconveniences, the interpolating process is performed at two stages.
In the case of switching the interpolating processes while using the same threshold value with resolution different from that of final printing, when printing is performed with high resolution, an inconvenience occurs in a case described as follows. For example, when it is assumed that there is original image data of 170 dpi and that of 185 dpi, the former one is subjected to the cubic interpolation to 180 dpi or higher and then subjected to the nearest interpolation to 720 dpi. For convenience of the operating process, the interpolation of integer times is performed by the cubic method, so that the data is interpolated to 340 dpi by the cubic method. On the other hand, the inputted image of 185 dpi is interpolated to 720 dpi by the nearest method without being subjected to the cubic interpolation.
In this case, the former is interpolated to 340 dpi by the cubic method, so that its picture quality is improved. On the other hand, the latter is interpolated only by the nearest method. Consequently, a reverse phenomenon such that although the former original image data is interior to the latter, an output of the former data has higher picture quality occurs.
The invention has been achieved in consideration of the above problems and its object is to provided a medium on which a printing control program which can execute optimum printing in a state where printing quality is instructed directly or indirectly is recorded, a printing control method, and a printing control apparatus.
In order to achieve the object, the invention according to claim 1 relates to a medium on which a printing control program for inputting image data obtained by expressing an image by pixels in a dot matrix state and allowing a computer to execute an interpolating process and a printing control process so that the image data is printed by a printing apparatus is recorded, wherein printing quality at the time of allowing the printing apparatus to print the image data is obtained, an interpolating process which is to correspond to the obtained printing quality is determined, and the computer is allowed to execute the printing control process by the determined interpolating process.
In the invention according to claim 1 having the configuration as mentioned above, by executing the process of the printing control by the computer, the image data obtained by expressing an image by pixels in the dot matrix state is inputted and is allowed to be printed by the printing apparatus.
The printing quality in the printing apparatus is not uniform. First, the printing quality at the time of performing printing by the printing apparatus by using the image data is obtained. When the printing quality is obtained, an interpolating process corresponding to the printing quality at the time of performing the printing by the printing apparatus is determined. The interpolating process is various. By preliminarily associating the printing quality and the kind of the interpolating process, the interpolating process can be determined from the printing quality. While executing the determined interpolating process, the printing control process is executed.
The recording medium can be, of course, a magnetic recording medium or a magneto-optic recording medium. Any recording media which will be developed in future can be similarly considered. The stages of duplication such as primary duplicate or secondary duplicate are regarded as the same without any doubt. The invention is also applied to the case where a communication line is used as a supplying method.
Further, the case where a part is realized by software and a part is realized by hardware is also included in the idea of the invention. A form in which a part is recorded on a recording medium and properly read as necessary may be also used.
In the case of carrying out the invention by software, the invention is realized as a medium on which a program is recorded. Moreover, it is natural that the invention is realized as a program itself. The program itself is also included in the invention.
As mentioned above, the method of preliminarily associating the printing quality and the printing control element and determining the printing control element from the printing quality is realized by a substantial computer. It can be easily understood that the invention can be applied as a substantial apparatus including such a computer in this sense. The invention according to claim 8 relates to a printing control apparatus for receiving image data obtained by expressing an image by pixels in a dot matrix state and printing the image data by a printing apparatus, characterized by comprising: a printing quality obtaining unit for obtaining printing quality when the printing apparatus is allowed to perform printing by using the image data; an interpolating process determining unit for determining an interpolating process which is to correspond to the obtained printing quality; and a printing control unit for executing the determined interpolating process and executing a printing control on the printing apparatus.
That is, it is surely effective as a substantial apparatus controlled by the computer. Such a printing control apparatus may be carried out by itself or may be executed by another method in a state where the apparatus is assembled in certain equipment. The idea of the invention is not limited to the above but includes various modes and can be properly modified.
When the medium on which such a printing control program is recorded is proceeded according to the control, it is natural that the invention basically exists in the procedure. It is easily understood that the invention can be applied as a method. Consequently, the invention according to claim 15 relates to a printing control method of receiving image data obtained by expressing an image by pixels in a dot matrix state and printing the image data by a printing apparatus, characterized by comprising: a step of obtaining printing quality when the printing apparatus is allowed to perform printing by using the image data; a step of determining an interpolating process which is to correspond to the obtained printing quality; and a step of executing the determined interpolating process and executing a printing control on the printing apparatus.
That is, the invention is not always limited to a substantial medium but is surely effective as a method.